Larger than the New Zealand lesser short-tailed bat, there have been no confirmed sightings of this species since 1965[3] and it is considered to be critically endangered, if not extinct.

[2] M. robusta was not considered to be separate from the New Zealand lesser short-tailed bat (Mystacina tuberculata) until 1962, when it was suggested as a subspecies.

After capturing a few and putting them in a cage they crawled around on the floor,[9] much like New Zealand lesser short-tailed bats are known to do.

[8] Sub-fossil evidence suggests that M. robusta was widespread throughout New Zealand until the arrival of the Polynesian rat (kiore).

[4] M. robusta, not recognized as a separate species at the time, was not considered a priority for conservation effort and was believed to have subsequently become extinct, last seen in 1965.

[2] As a result of this evidence the IUCN status of the species, formerly listed as extinct, has been changed to 'critically endangered'[1] and the New Zealand threat classification is currently 'data deficient'.